This invention relates to a chuck assembly with a bit, and particularly to the structure of the chuck, and the structure of the assembled chuck and bit.
For many years, chucks have been used to grip or mount bits for a variety of purposes, including the mounting of rotary bits for use with a hand or power tool. In many instances, chucks have included a plurality of movable bit-engaging jaws mounted within an opening of a chuck body. The jaws can be manipulated to clamp the shank of a bit which has been inserted into the opening of the chuck. In this manner, the bit is retained with the chuck which, in turn, is mounted on the hand or power tool. The jaws of such chucks may be operated by use of an external implement, such as a conventional chuck key, or by rotational elements on the chuck.
Other chucks of the past were designed to allow the bit to be inserted directly into the opening of the chuck using a direct-insertion mounting technique, whereby the bit is locked in assembly with the chuck by virtue of structure within a body of the chuck and on the bit.
While some of the above-noted chucks are adapted to receive and mount bits by insertion of the bits directly into the bit-receiving opening of the chuck, the opening is typically designed to receive only shanks of bits with a common diameter or size, consistent with the diameter or size of the opening. Thus, a set of bits of different diameters at the working ends thereof would each be required to have a chuck-mounting shank diameter which is the same as the shank diameter of the remaining bits of the set. This leads to a situation where the bit shank, in order to be strong enough to handle the forces and torques imposed on the larger bits of a range of sizes employed, is much larger than needed, and thus uneconomical, for the smallest bits of the set.
Thus, there is a need for a chuck having structure which will facilitate use of the direct-insertion mounting technique for bits having different shank diameters.
In addition, there is a need for a chuck and bit assembly having structure which facilitates use of the direct-insertion mounting technique where the parameters of the chuck structure are constant and the parameters of the structure of the bits fluctuates.
It is, therefore, an object of this invention to provide a chuck having consistent structure which will facilitate use of a direct-insertion mounting technique for bits having different chuck-mounting shank diameters.
Another object of this invention is to provide a chuck and bit assembly, each having structure which facilitates use of a direct-insertion mounting technique where parameters of the structure of the chuck are constant and parameters of the structure of the bits fluctuates.
With these and other objects in mind, this invention contemplates a chuck for receiving and supporting a bit, which includes a body formed along an axis thereof having an axial opening accessible from a forward end of the body for receipt of a shank of the bit. A radial passage is formed in the body in communication with the axial opening within the body. A limit surface is formed on the body adjacent the radial passage, and a compression member is located movably within the radial passage and has at least a portion which is extendable from the radial passage into the axial opening. A support extends from the compression member and is positioned for engagement with the limit surface to limit the extent of movement of the at least a portion of the compression member into the axial opening.
This invention further contemplates a chuck for receiving and supporting a bit, which includes a body formed along an axis thereof and having an axial opening for receipt of a shank of the bit, with the opening being accessible from a forward end of the body. A compression member is located movably in the body and has at least a portion which is extendable into the axial opening. A nosepiece is attached to the forward end of the body. At least one jaw extends from a rear face of the nosepiece in a direction axially toward a rear end of the body and is located in the opening of the body.
In another aspect, this invention contemplates a chuck and bit assembly, wherein the chuck includes a body formed along an axis thereof and having an axial opening for receipt of a shank of the bit, with the opening being accessible from a forward end of the body. A jaw is located within the opening of the body in an axial direction thereof. A radial passage is formed in the body in communication with the axial opening within the body. A limit surface is formed on the body adjacent the radial passage, and a compression member is located movably within the radial passage and has at least an extendable portion which is extendable into the axial opening. A support extends from the compression member and is positioned for engagement with the limit surface to limit the extent of movement of the extendable portion of the compression member into the axial opening. Means are provided for urging the extendable portion of the compression member toward the axis of the body. A bit includes a chuck-mountable shank formed along an axis thereof wherein the shank is formed with spaced exterior surface areas positionable adjacent the extendable portion of the compression member and the at least one jaw upon positioning of the shank within the axial opening of the body. The means for urging then facilitates the clamping of the shank between the compression member and the jaw.
Other objects, features and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiment, the appended claims and the accompanying drawings.